#thermistor
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- เผยแพร่เมื่อ 17 ต.ค. 2024
- Project Code Here:
ccbsp6qd6kmk4z...
A thermistor is a special type of resistor whose resistance changes significantly with the temperature.
Operating Temperature Range:
-67 to 490F (-55C - 250C)
Here we have two regular 10K resistors in series, configured as a voltage divider. This is a way to use resistors to set a specific voltage.
If we start with 5V and measure in between the two 10K resistors we get 2.5V, half of the source voltage.
Show formula
At 77 degrees Fahrenheit, a 10K thermistor will measure at 10,000 ohms. Now if we replace one of those 10K resistors with a 10K thermistor, we will get a variable voltage depending on the temperature.
If we connect this junction to a microcontroller’s analog input we can read this voltage and run a formula to convert that reading into a temperature… then we send that reading to a display.
I added a button and additional code to switch between Celsius and Fahrenheit.
I’m curious to see if my code works for triple digits…
(Use a torch to heat it)
How about negative numbers…
(spray it with canned air)
Because of the tolerance in the various components, we can’t expect this to be 100% accurate straight away. So I’m going to replace the other 10K resistor with a potentiometer so we can have a way to calibrate it.
A thermistor is another highly valuable sensor you can add to your DIY toolkit. You can buy a pack of 50 for like $7 on Amazon!
This project is more than a practical tool, it’s an excellent introduction to the world of electronics and Arduino.
#thermistorproject
#arduinoproject
#arduino
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This is accidentally the best explanation of a voltage divider
I just understood it this time while watching the short lol.
What's that now ?
Or should I Google it ?
Rather please explain so that other readers can know.
And the theory of thermostats and how theyd be made👍 this was neat makes me wanna do some trig
on practical side yes
but not theoretical side
i think beginners need both, i have seen students who learnt theory but doesnt know why it s there or how to use it
Also a good way of describing how transducers work in Electronics
When I was first learning how to plan and layout PCBs, a wise man once told me "everything measures temperature" it's just a matter of how linear the usable range is.
Will definitely remember that
that was a very wise man :)
plot twist: all resistors are thermistors!
They are all heaters too but I wouldn't use them like that primarily.
@@Bobsmith-yf9oy some would
aluminium cased resistor
Well, yes... But actually no. Regular resistors are not at all precise in this application. The ∆R isn't very consistent per ∆° in a standard resistor because they're designed to provide consistent resistance under a variety of conditions. Thermistors are designed to provide a consistent ∆R/° and, thus, are far better for the application. A standard resistor will tell you if it's getting hotter or colder, but not the actual temperature; at least not consistently.
@@taitano12How are special resistors made that stay constant in large temperature intervals?
@@fatitankeris6327 I'm not sure how they're made, though I probably learned it at some point. But it's not that they don't stay constant so much as vary by predictable and consistent amounts. Most resistors can change resistance inconsistently . You'll change by half an Ohm from 20-22°, half that for 22-27°, and nearly an Ohm for 27-31°. Then, the next time you use that same resistor, the resistance changes won't match up; getting a quarter Ohm for 20-22° and so on. It seems to plague wire wound resistors the most. It's like how a diode is also an LED and light sensor, but is almost useless as such due to chemistry and manufacturing processes.
"I added a button to switch between Celsius and nonsense"
This made me actually laugh out loud 😂
Celsius is a measure of temperature relative to water, and Fahrenheit is a measure of temperature relative to humans. It makes sense to use them as percentage values based on what is being measured.
E.g. it is 60% hot outside, this water is -5% warm.
I believe Kelvin is better than both
True since it's based on the very laws of the universe.@@Cubikat
True
You could also run the output of the thermistor to a speed controler for a fan and cause the fan's speed to increase with the temperature...
Oh thank god - at long last!!
Ive seen so many beginners tryingvto teach electronics, and getting it very wrong. Classic Dunning Kruger, they don't even know how little they know.
By contrast, this is correct, very clear, step by step. Brilliant, again thank you.
...... unless- you are one of those Dunning-Kruger victims yourself, and sadly there is no way to self-realise the fact. Even PhDs, in the relevant sphere, they say, are no defence. Very sad! It's also possible that Dunning and Kruger had no idea what they were talking about. Best wishes.
Celsius is universal. Most modules are calibrated to Celsius and then convert to Fahrenheit if necessary. That's why an iPhone won't display 69°F. It reads in C and converts. Sticking with a module's native measurement and being compliant with most of the planet is clearly beneficial.
One might as well ask an airline pilot if there's a benefit to learning English. Compliance to standards is always beneficial.
Most standards, however, aren't global. Ask anyone in the u.s. if 30c is hot or cold, most won't be able to tell you. You build for the market you're trying to attract.
Fahrenheit was preferred in many metric countries until digital and was able see 0.1 etc. of C easily. Degrees F is a smaller scale per degree and was preferred over C for accurate temperature control. Today though F is just a Civilian American unit. NASA etc. have all standardized to C.
For everyday use in most of the world, you'd want Celsius. For certain scientific or engineering applications you might want Kelvin.
@@Klairity "Was" is the important point.
@@rileyjones7231 The US is only one of like six tiny countries still using F, and then only amongst the civilian population. They're up there with Micronesia and the Marshall Islands.
Bro accidentally published the best explanation for voltage divider
Dude just brought up flashbacks of losing points on an exam for forgetting what it was called and calling it a voltage splitter.
And thermisters work as a pretty decent substitute fuse too
Everything is a fuse, if you're wealthy enough
@@Klaevin😂😂 true
I was working for a company doing industrial wiring.
We threw away thermistors that weren't up to spec, so I yoinked one from the bin.
Years later, I built myself a new PC and the fans were making a lot of noise from spinning too fast.
So I put an arduino between the fans and the PSU so that I could spin the fans according to the temperature of the thermistor I could finally use.
I learned a lot about pull down Resistors and mosfets that day (I got the mosfets from an old printer)
I knew how a thermistor worked, but I just now realized the word 'thermistor' is a combination of 'thermal' and 'resistor'
"I was today years old..." 🤣
TRRANsfer reSISTance : TRANSISTor
DIode/TRIode for Alternating Current: DIAC / TRIAC
😉
Yeah it's actually a nonsense word lol
@@DerMarkus1982 Am I having a stroke?
Absolutely fascinating! Very clear explanation!
At 100 degrees Celsius the water boils, at 0 degrees it freezes. So yes, Celsius is better =)
At standard 1atm, sure. Still arbitrary and moveable, not to mention the fact that choosing the properties of water specifically is another arbitrary choice based on circumstances and utility within those confines. Kelvin beats both Celsius and Fahrenheit every time.
At 100 degrees Fahrenheit it feels really hot, at 0 degrees it feels really cold. Fahrenheit is for people living every-day life… Celsius is for doing science stuff.
@@Guynhistruckkelvin is just Celsius shifted it doesn't really make a difference.
You used “so” but forgot to explain how it’s better
@@thumper88888 Read the first line in my comment again ;)
This is brilliant. Sometimes you need a ballpark temperature figure without adding too much cost to your circuit. Genius.
I don't have many arguments for °F or °C. Other than that °C corresponds nicely to Kelvins which makes them much nicer to work with in calculations.
Also they are not perfectly linear
Their datasheet should give the coefficients so you don't have to hack with the potentiometer
since it not linear, can we use code make it linear?
@@avadementia6889 yep you can have linear approximation if you want something but it will drift in and out of accuracy. You can have a polynomial; The datasheet will give at least it should the coefficients for a 2nd or 3rd order equation and the code will calculate it within the accuracy of the thermistors. These coefficients are determined at manufacture from a bin of components within a gaussasian distro so u need to check the datasheet
@@bobodyuknow thanks for the information 🙏
@@avadementia6889 Easier to go with a PTC thermistor, those only need 1 cal. point. NTC's need 3 cal. points. A problem connecting this simple way, is that they get warm cause of the current, thus sensing the wrong temperature.
Use a wheat stone bridge rather than a straight voltage divider. Much more stable.
Show off!
@@neps4th And proud of it =)
Your components are so nice and shiny and aesthetic!
Celsius for the real use case and Fahrenheit for a fantasy system. 😂
I don’t know very much at all about circuits and this explained this very part extremely well
Amazing! Didnt know i needed to know this and now im glad i do.
Dude this is brilliant. Looking to crash course and info like this just clicks everything into place to get going. Well done!
Could you not also adjust the variance in the code? I realized the benefit of the potentiometer being easier to adjust, but just curious if there's a physical reason to do so.
Yes you can.
The use of a potentiometer as he has done is not good. The thermistor response to temperature is non linear and a potentiometer does not correct for that.
A potentiometer might be useful to make the range of voltage produced over the required temperature range fall within the voltage input range of the DAC but it can't correct for the non linear response of the thermistor.
The most accurate way therefore is to store a look up table (or calculate it mathematically) mapping the input voltage to temperature.
Nice... as an analog guy my only achievement with a nano is to blink a led in Morse code. C and its zeros & ones I find perplexing.
Celsius! Nothing makes more sense than the water freezing temperature as a standard base!!
Celsius makes zero sense
@@MikehMike01 It makes more sense than farheinheit
Here is my code for this project... create.arduino.cc/editor/hackmakemodcommunity/f8c6e252-c347-4dd4-b413-cfd8e3d7111b/preview
ADCvalue should be divided by 1024 and not by 1023 because it's how ADC works. Classic misunderstanding ;)
What a quality video!
The potentiometer to calibrate is so simple but clever!
Celsius is much better!
Of course. Who thinks it is even in doubt?
@@Bobsmith-yf9oy Americans?
@@jakesteampson7043Fahrenheit is better for day by day since its on a scale so it makes alot more sense like 0 is really cold 50 is in the middle and 100 is hot
@@partyethtoon Maybe, but whats's Fahrenheit based on, so you know how cold 0 is and how hot 100 is? Without a clear reference it's just arbitrary numbers
@@jakesteampson7043 it’s not arbitrary, but leave it to a European to be uneducated and smug
Literally all of this was awesome to see and learn. Cool stuff.
Cool, now do strain gauges.
I used one of these to make digital thermostat for my house furnace. It's even powered from the furnace. It's been running continuously for the last 5 years.
"Thermistor?! I barely know her!"
😅😅😅
I like OG Celsius, the Celsius we use now is actually Centigrade. OG Celsius had 0 at the boiling point of water and 100 at the freezing point
C° definitely better, because it's simple and most of the planet uses it 🎉
How is it simple? I don't understand it.
Fahrenheit is a 0-100 scale of how hot it feels outside. That's simple. And quite frankly, I don't care what "most of the planet" uses.
@@PIVfirestarkproducon only 4,5% of the population use it and you defend it with everything you can because of the sunken cost fallacy. Your stance only proves how egocentric America is.
Fahrenheit doesn't have a use. Period.
What you learned by experiencing world in °F can be as easily or even more learned in °C, but you can't do the same vice versa.
Fahrenheit was literally based off the freezing temperature of a random solution of brine made from a mixture of water, ice, and ammonium chloride (a salt), that nobody can ever repeat because of missing records. 100°F also isn't the human temperature any more as it has been measured that body temperature decreases over generations.
Below 0°F and above 100°F is also nonsense as you could freeze to death with much higher values than 0°F and you could safely withstand temperatures well above 100°F for prolonged periods of time. Learning what is and isn't actually comfortable equally applies to both scales, so there is NO benefit of either in this regard. You need to experience both. 100°F is "only" 37°C, we sometimes get temperatures reaching 40°C or 104°F and I have experienced even more when abroad in summer. And 0°F is frikkin -18°C, which is well below freezing, that's all I need to know. What is practical is 0°C or 32°F at which point I know whether it will rain or snow or whether the roads will be frozen. But since we are reasoning about freezing being the turning point, it only makes sense to base the whole scale off it, instead of some random solution and temperature at that time.
The real benefit of Celsius over Fahrenheit comes from the real practical use.
With Fahrenheits you need to remember freezing 32°F, cool room 68°F, (arguably also body 98.6°F) and boiling 212°F.
With Celsius you just need to remember two values: cool room 20°C and body 37°C. The freezing and boiling points are inherent to the scale.
Freezing is the most important of all as it determines whole load of things. Can I drink the content of this can at all? Will the water in the pipes tear them apart? Will it rain or snow? Are the roads frosted? Will I slip and injure myself on the stairs?
Now to the practical use, not at all scientific, lmao. You will know how important this is when you have small babies.
Can you tell just like that, that 140°F is twice as hot as -1°F?
Is it obvious to you that if you mix 1 unit of 140°F water with 1 unit of -7°F water, that you'll end up with 2 units of 104°F water?
In celsius, the same values as above would be:
60°C twice as hot as 30°C
1unit 60°C + 1unit 20°C gives 2units 40°C
Hope this helped you understand "how simple it is".
@@PIVfirestarkproduconthats not how it works 💀💀💀
@@PIVfirestarkproducon Ah yes, it's 72% of "hot" outside today... If only we knew how hot the "100% hot" was. Meanwhile if you see 50°C you immediately go "Oh shit, it's halfway up to boiling outside"
PS. Don't forget that the "idc what most of the planet uses" attitude cost you a $125'000'000 Mars probe x3
@@PIVfirestarkproducon 100F is 37.77C which is temperature of what?
0F is -17.77 which is tempeartue of what?
How is Celcius scale simple?
0C is the point where water freezes
36.6C is normal human body temperature
100C is the point where water boils
comparing to 32F 97.88F and 212F ... 0 36.6 and 100 look way simplier
Thermistors are great for monitoring system temperatures and preventing overheating.
Pretty cool how these tiny components can measure "tempeture"
You should calibrate in software. You’re not going to accidentally change the value in code, but you may accidentally bump into that potentiometer. Dust and debris can also wear down potentiometers, causing them to drift slightly, which normally isn’t a problem unless its as severe as with modern controllers, but in something as precise as temperature, it matters
You can probably calibrate the error out in software to avoid using expensive components :)
I wonder if you could get a more accurate temperature by averaging multiple thermistors?
Kelvin is the only value not based on subjective/random standards. Zero is the point of absolute zero. Seems logical. Even more to the point when it comes to the video, the Steinhart-Hart Equation used to calculate the thermistor curve uses kelvin for it's temperature variables. 🖐️🎤 🤓
YES. Celsius is just as stupid and arbitrary a scale as Fahrenheit.
Not the only one, Rankine is the same, but based on Fahrenheit instead of Celsius.
@@Guynhistruckno. Kelvin is based on Celsius. So one degree K is the same as one degree C. So just add a konstant to C or K, and you have converted between them. No need for floating number calculations as F.
No clean connection to F.
@@GRBtutorialsno one uses Rankine.
There are a lot of other temperature scales that also isn't used any more...
Science and Technology uses K and C. Then concerts to F when in need. Like in the Apollo moon lander.
Celsius is a practical scale for everyday use in temperatures normally encountered by humans. It is just as accurate as Kelvin.
(When measuring your car-speed you don't add in the speed of the earth orbiting the sun.)
I feel like one of these could be a good way of getting random numbers no? Since how small it is could allow the temperature to change quickly enough to get some useful random number's.
As a European I would really appreciate you using C°
Nice video. Personally I would put the temperature correction in the code of the microcontroller. Less convenient if you need to recal but you avoid using a not so reliable part like a potentiometer.
As an American who is good with science and engineering, I know both but still prefer celsius over the nonsense that most people in my country use.
Very nice! You can further to calibrate the curve (the relationship between delta T and delta V) also, correct?
Fahrenheit is miles better for the average person since it is calibrated for how temperatures feel for us humans, 0 degrees being too cold and 100 being too hot. For scientists though I think Celsius is better.
So 50 degrees is just right? Because last time i checked its 10°C which is still cold
@rixuuu 🤣😂 no man, our body temperature is 98.6 so we're not going to prefer something between 0 and 100, we prefer something closer to 98.6. Plus, it's American so RAHHHHHHHHHHHHHHH, FREEDOM!!!!!!!!!
@heyhenrytech so if 50 is cold but 100 is too hot why bother with 0-50 and just cut it and then it would be 48°F for body 50 is now 0 and it would be even more intuitive where right in the middle (25° = about 75°F = 24°C) would be the perfect temperature, not too cold, not too hot. And water freezing temperature would be around -7° with new temperature system.
@rixuuu I think the reason they use 0 and 100 is because it makes more sense then the scale "starting" at 50.
@rixuuu also, by that logic 200 is also too hot so is 100 just right?
Wow this opens up a lot of possibilities
Celsius!
Fun fact, for measuring temperature for each core of a CPU, and for other areas of the silicon die as well. diodes are used as the temperature sensors. These are lithographed right on the silicon die with the rest of the billions of transistors.
This is how it sounds when someone speaks to you in a unknown language.
Thanks you helped me fix my cars thermometer by adding a potentiometer to tune it.
Celsius is better
fact
why have the potentiometer? didn't you do the calibration in the code?
Celsius and Kelvin. Fahrenheit seems unnecessary
I love metric, but neither F nor C are "better" since they both measure accurately. If anything, F is more accurate in that 1°F is a smaller step, so it's easier to appreciate the significance of the difference between 88°F and 89°F than it is between 31.1°C and 31.6°C. The "best" one practically speaking is the one most widely understood by your target audience.
C° is better
they're common in heating systems that use outdoor temperature to operate more efficiently.
they use a 10k thermistor outside for indoor temp control.
Fahrenheit suck
Amazing explanation.
For those building their own circuits, replace a voltage divider with a precision voltage reference. It will output a very accurate reference voltage which you can use in a microcontroller for calculation purposes. It requires very few external components, pretty cheap and they are agnostic of your input voltage (within a range). Youll find Arduinos have an AREF pin which is ideally where you would use a precision reference for analog to digital conversion. Most of the time its tied to 5V but 5V is never exactly 5.000V and so your application will always be inaccurate.
Fun fact, this is how aircraft engine fire detection systems work. The Kiddie system has a long grounded tube filled with the thermistor material and a single in it. As the temperature rises, the resistance of the thermistor decreases until an electrical connection is made between the conductor and tube, which alterts the pilots that theres a fire.
Thermistor is also subject to compound errors based on voltage bias, temperature and bias drift.
If you could run a formula then you don't need a potentiometer. You just need to tweak the formula a bit to adjust the value
You'd run a formula Everytime it deteriorates?
Fan controller with transistor and that diode. Neat.
They’re also an integral part of the head of a 3D Printer, monitoring the the temperature. Though they look a bit differently there, encased in glass to withstand several hundred degrees Celsius
The potentiometer is a neat idea but it can be adjusted out of calibration. Recalibrating in software would be more reliable.
This is great but generally temperature sensors are better made with a matched pair of BJT transistors - essentially their output current is also temperature sensitive and more stable (in short) over a wide range of temp.
This man is a genius
Very nice demonstration.. Thank..!
Well Celsius and Kelvin are linked in that +1 degree of either is the same change in temp, digital thermometers usually read in C and then convert to F, you will see this when 69f is never displayed, Most of the world uses C and K and dont now F at all. F has nothing going for it.
Thermistors are used in LiPo batteries and some devices require a battery with one built-in to be able to read its temperature.
that was kick ass dude.
°C: 0 = water changes its aggregate state
°F: 0 = well the coldes temp in Danzig where I live 🤪
One minute of POW! This is how it's done.
May I ask what camera you are using? The quality is amazing
Tunnel diodes?? Might be a cool topic. Nice short!
Should you use multiple thermistors and average out the result or use a better sensor for accurate readings?
I have absolutely zero idea about this subject. Sure was entertaining!
Calibrating with a potentiometer is only accurate at 73 degrees, thermister output is very non linear...will have to build a chart of calibration offsets for every few fegrees for accurate temperature readings over a large range
There are very small and cheap integrated circuits that have all the compensation and calibration built it, that you can use to measure temperature very precisely.
This short looks so good on HDR... Wow
I had that in itt technical institute,building and understanding of control and computer boards from scratch and how to read resisters,capacitors and measure hertz and frequency’s of a wave length using that oscilloscope machine
Ive done a bunch of DIY repairs on appliances, and its almost always the thermistor that goes out lmao
This may or may not surprise you, but in commercial refrigeration a solid 10% of the calls is a bad thermistor, or is a result of a bad thermistor.
I like how the reading can be tuned for accuracy! Would love to teach my son how to replicate this experiment for himself one day, hes only 4 now. 😂
Is it more accurate than a thermocouple? I would've thought the best use for this is to use it as a bypass to turn on/off when at temperature.
Quite a good video. I once built temperature protection for a fm transmitter using a thermistor and comparator. I often wondered how hard would it be to add an lcd to the transmitter with live readout of the rf mosfet temperature 😊
Bro is spitting BARS
The potentiometer is pretty smart..
You can use a negative temperature coefficient thermistor to remove 'bell tinkle' from a badly wired parallel bell phone.
Good info cool video! Love your stuff gettiing into more in-depth repairs you and learn electronics repair are a big help
Glad you like them!
F° or C° which one is better??
My brother casually starting a war in the comment section!!!
Fun fact: thermistors have a negative temperature coefficient, meaning they decrease in resistance as they heat up
I had to learn how to do this with an arduino last year, it was fun.
That looks like a DIAC but I checked and I'm wrong again.
But you can use the forward voltage of a signal diode to measure temperature. You'll find a diode on an engine air intake measuring air temperature.
This is actually used commonly on 3d printers
You can also use a diode within limits.
Beautiful info
Instead of a readout you could also hook it up to a fan to control it.
The best thing i saw today